Not applicable.
Not applicable.
A tilting trailer is a unique and useful variation of a standard trailer. As with any trailer it is used to haul material and equipment and the tilting of the bed allows the user greater ease of loading and unloading cargo. Several configurations of tilting trailers have been invented in the past. A simple tilting trailer is configured with a standard axle (with its axis running through the wheels) and the bed tilts around that axle. This creates a tilting angle that is very steep and which may or may not be desirable. Where low tilt angles are desired, a trailer configuration with an offset axle is very effective and is the subject of the present invention. Such trailers are useful for the loading of rolling equipment such as lawnmowers and motorcycles where loading with a ramp is impractical.
The present invention is an improvement on the trailers described in U.S. Pat. No. 3,860,255 to Rodriguez, and U.S. Pat. No. 4,659,100 to Welker. These patents describe trailers with a configuration having two principle assemblies hingedly connected together towards the rear ends of the assemblies. A pair of stub axles mount wheels directly to the outer frame assembly. The tilting is accomplished by raising the forward portion of the outer frame assembly and thus raising the wheels and lowering the rear of the trailer to the ground.
Because the stub axles are rigidly affixed to the perimeter frame, they provide no effective suspension. Various suspension means have been devised for this configuration to alleviate to effects of rough terrain on the trailer. The aforementioned Welker patent uses a spring attachment for the forward portion of the outer frame so that it may move with variations in road surface. The limitation with this configuration that the distance between the spring and the stub axle means the full travel of the spring device will result in very little movement of the stub axles effectively eliminating any practical benefits of the suspension.
Other approaches have used leaf springs in an attempt to provide suspension for this type of trailer. Such approaches are exemplified in U.S. Pat. No. 3,746,195 to Beilke and U.S. Pat. No. 3,788,675. Leaf spring suspensions are inherently rough riding when unloaded and provide no damping effects unless also configured with a shock absorber.
It is an object of this invention to provide a suspension for a tilting trailer that provides better spring characteristics and damping qualities over prior art and does not limit the tilting capability of the trailer.
A suspension configuration for a tilting trailer according to the present invention comprising a main load carrying deck with individual swingarms pivotally mounted to each side of the deck. Each swingarm is forwardly disposed and has a stub axle mounted to the forward end for wheel attachment. Tilting means comprises a generally U-shaped frame pivotally mounted to the rearward end of each swingarm and extending over each swingarm to a latch point at the front portion of the main deck. A resilient spring means is affixed between the bottom portion of the U-shaped frame and the top of each swingarm near the stub axles.